[PATCH v4 6/6] bootconfig: Share the checksum function with tools

[Masami Hiramatsu <mhiramat@kernel.org>]

Move the checksum calculation function into the header for sharing it
with tools/bootconfig.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 include/linux/bootconfig.h |   20 ++++++++++++++++++++
 init/main.c                |   12 +-----------
 tools/bootconfig/main.c    |   15 ++-------------
 3 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
index e49043ac77c9..6bdd94cff4e2 100644
--- a/include/linux/bootconfig.h
+++ b/include/linux/bootconfig.h
@@ -16,6 +16,26 @@
 #define BOOTCONFIG_ALIGN	(1 << BOOTCONFIG_ALIGN_SHIFT)
 #define BOOTCONFIG_ALIGN_MASK	(BOOTCONFIG_ALIGN - 1)
 
+/**
+ * xbc_calc_checksum() - Calculate checksum of bootconfig
+ * @data: Bootconfig data.
+ * @size: The size of the bootconfig data.
+ *
+ * Calculate the checksum value of the bootconfig data.
+ * The checksum will be used with the BOOTCONFIG_MAGIC and the size for
+ * embedding the bootconfig in the initrd image.
+ */
+static inline __init u32 xbc_calc_checksum(void *data, u32 size)
+{
+	unsigned char *p = data;
+	u32 ret = 0;
+
+	while (size--)
+		ret += *p++;
+
+	return ret;
+}
+
 /* XBC tree node */
 struct xbc_node {
 	u16 next;
diff --git a/init/main.c b/init/main.c
index eb01e121d2f1..43914e675421 100644
--- a/init/main.c
+++ b/init/main.c
@@ -386,16 +386,6 @@ static char * __init xbc_make_cmdline(const char *key)
 	return new_cmdline;
 }
 
-static u32 boot_config_checksum(unsigned char *p, u32 size)
-{
-	u32 ret = 0;
-
-	while (size--)
-		ret += *p++;
-
-	return ret;
-}
-
 static int __init bootconfig_params(char *param, char *val,
 				    const char *unused, void *arg)
 {
@@ -439,7 +429,7 @@ static void __init setup_boot_config(void)
 		return;
 	}
 
-	if (boot_config_checksum((unsigned char *)data, size) != csum) {
+	if (xbc_calc_checksum(data, size) != csum) {
 		pr_err("bootconfig checksum failed\n");
 		return;
 	}
diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
index f5b564206428..483a948af522 100644
--- a/tools/bootconfig/main.c
+++ b/tools/bootconfig/main.c
@@ -128,17 +128,6 @@ static void xbc_show_list(void)
 	}
 }
 
-/* Simple real checksum */
-static int checksum(unsigned char *buf, int len)
-{
-	int i, sum = 0;
-
-	for (i = 0; i < len; i++)
-		sum += buf[i];
-
-	return sum;
-}
-
 #define PAGE_SIZE	4096
 
 static int load_xbc_fd(int fd, char **buf, int size)
@@ -234,7 +223,7 @@ static int load_xbc_from_initrd(int fd, char **buf)
 		return ret;
 
 	/* Wrong Checksum */
-	rcsum = checksum((unsigned char *)*buf, size);
+	rcsum = xbc_calc_checksum(*buf, size);
 	if (csum != rcsum) {
 		pr_err("checksum error: %d != %d\n", csum, rcsum);
 		return -EINVAL;
@@ -383,7 +372,7 @@ static int apply_xbc(const char *path, const char *xbc_path)
 		return ret;
 	}
 	size = strlen(buf) + 1;
-	csum = checksum((unsigned char *)buf, size);
+	csum = xbc_calc_checksum(buf, size);
 
 	/* Backup the bootconfig data */
 	data = calloc(size + BOOTCONFIG_ALIGN +